Corrosion control program

To have an effective corrosion-control program, the following suggestions should be considered ... 

Summer months in these areas may not necessarily be any better. In view of these problems, it is very important to consider all aspects of operation before embarking on the project. Therefore, before starting a drilling project, corrosion control must also be considered. Steps should be taken to ensure running an effective corrosion control program. 

Procedures shall be established for evaluating the need for and effectiveness of a corrosion control program. Corrective actions commensurate with the conditions found shall be taken. 

GR-5.3.1.3 Internal Corrosion. An internal corrosion control program shall include the following ... 

Since HtS dissolved in water is very corrosive to carbon 4 steel, a comprehensive corrosion-control program is being conducted. In the field, each well is treated once per month by displacing inhibitor down to the perfora-. tions with stock tank oil. Corrosion coupons in the flow-lines are inspected every 6 months Little corrosion has been detected in the field. In the plants, corrosion in-hibitor is added daily to the gas-sweetening solvent, the salt water system, and the stabilizer overhead. Inhibitor is -Jj also added to bulk chemicals as received. Numerous corrosion coupons and probes are installed in each facility and are pulled for inspection every 1 to 3 months Corrosion rates have been low (less than I mil/year) asY result of the inhibitor injection program. 

Effective corrosion control programs are essential in reducing unit downtimes. To be effective, the program must address not only specific corrosion problems, but anticipate and prevent them as well. Consequently, effective pretreatment in addition to other corrosion control measures is important. 

Corrosion detection plays an important role in any corrosion control program. Most of the methods employ nondestructive test methods and include hydrogen evaluation, radiography, dynamic pressure, corrosion probes, strain gauges and eddy current measurements. Of these, the methods employed in cooling tower practice are hydrogen evaluation and corrosion probes. 

Four types of evidence - metallurgical, microbiological, chemical, and electrochemical -are generally used to determine if the influence of the organisms is important enough to invoke a corrosion control program. (Dexter)5... 

Protection of cooling system metals involves complex interrelated problems of scale and deposit prevention, control of microbiological growths and other fouling sources, in addition to corrosion mitigation by inhibitors. Corrosion control programs may be expected to vary considerably between systems, since each installation presents different environmental factors and operating problems which affect response. 

Table 4.34 represents a corrosion control program implementation flowchart for internal corrosion. 

Improper repairs Poor corrosion control Program or lack of implementation Poor training... 

Corwith JR, Westermark RV. The downhole corrosion control program at Ekofisk. Inspection, Maintenance and Repair, Febr. 1984. 

Virtually all definitive test work is done in a pilot plant or plant. The final test is performance of actual operating equipment. A systematic, quantitative inspection program is the final measure of success of a corrosion control program. All other methods are evaluated in terms of how closely they approximate this method. Other methods used are listed and described briefly below. 

Areas Improper repairs Inadequate corrosion control program or lack of implementation Inadequate training Ignorance of corrosion Plugged drain systems... 

Figure 8.2 Corrosion control program implementation flowchart.

Several attempts have been made to develop an index that would predict whether a water is corrosive or not, however, these attempts have not been successful. Several indices have been developed over the years. Some of these indices can be used in corrosion control programs. The two most common indices used are Langelier Saturation Index (LSI) and Aggressive Index (AI), which are summarized below. 

In an idealized corrosion control program, inspection and maintenance would be applied only where and when they are actually needed, as reflected by the maintenance on demand (MOD) concept. In principle, the information obtained from corrosion monitoring systems can be of great assistance in reaching this goal. Conceptually, the application of a monitoring system essentially creates a smart structure, which ideally reveals when and where corrective action is required. 

Inhibitor residuals are occasionally used to monitor corrosion control programs. By knowing at what concentration certain water soluble inhibitors give protection, we can generally tell if protection is being accomphshed. 

Production losses during shut-downs are the major economic concern. The frequency of periodic shut-downs for maintenance and inspection depends on the rehabihty of the corrosion control program. The more corrosion control apphed, the fewer shut-downs will occur in the system. Thus, less time is lost from scheduled shut-downs. The frequency of costly, unscheduled outages can reduce even more drastically. 

Successful corrosion control programs depend both on proper application techniques of the protective chemicals and good monitoring. Consistent record keeping by both the supplier and the customer is an essential part of a successful monitoring program. 

The crude unit corrosion control program was inadequate they did not take timely corrective actions to prevent plugging and excessive corrosion in the piping (CSFIIB 1999). 

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